UPS invoice error

[mrguyii]

I shipped UPS via eBay Shipping at a quoted charge of $11.62. After I dropped the package off at a UPS access point, the buyer requested an address change, which I was unable to do. The buyer contacted UPS and rerouted the package.  A few days later, I received an invoice from eBay for $29.62 which is $18 more than the quoted/calculated charge. I have been unable to get a call through to eBay.  eBay should have a 24 hr customer service call center, this  "Monday to Sunday 5:00 am to 6:00 pm PT" time restriction seems like a strategy to kill the will of customers to had their issues disputed.